It is well known in the art that in the upper off-center position of the ingot casted by ordinary casting mold, there exists a V-shape area enriching of segregates and inclusions. The segregates and inclusions in this area are hard to be removed because of being located in the upper central portion. In this case, it leads to two possibilities: one is to ensure the quality of the metal by sacrificing more than half of the metal yield; the other one is to ensure certain metal yield by lowering its quality. However, both of the two possibilities are not what desired.
Currently, most of metal ingots in the world are still casted in this way, and thus a lot of metal cannot be got with a high quality and cannot to be used effectively and fully, which cause much energy wasting.
And in order to get clean metal, a secondary melting refining procedure, such as electroslag remelting is needed. This causes a great wasting of manpower and resource. Additionally, a great pressure is also imposed on the environment.
This does not meet the development requirements of energy saving and environmental protection, which is the great loss of the metal smelting industry.
In addition, because the efficiency is particularly low, especially the electric arc could seriously damage the crystallizer, a crystallizer mold in the manner of electroslag furnace remelting can only refine scores of furnace of steel, which increases the cost of production.
In practice, many customers need large metal pieces having an annular, tubular or sleeve shape, and the products are mostly produced by forging punching. However, if the desired product needs a larger hole, more time and energy will be required for punching and reaming, which leads to the increasing of production cost.